Engineering Commons^™

Noise And Gain Characterization Of Interband Cascade Infrared Photodetectors, Eli A. Garduño

Electrical and Computer Engineering ETDs

Infrared (IR) detectors are an enabling technology for a broad and growing list of applications including gas detection, night vision, and space-based missile warning. There are ongoing efforts in IR detector research to explore the potential of new material systems and energy band structures in addition to continuously improving their sensitivity through increasing their quantum efficiency and lowering their dark current and noise. This dissertation examines an emerging class of IR detectors known as Interband Cascade Infrared Photodetectors (ICIPs).

ICIPs contain multiple regions to facilitate the collection of photogenerated electrons and to limit unwanted dark current. Theory regarding their performance …

Frequency Domain Decomposition Of Digital Video Containing Multiple Moving Objects, Victor M. Stone

Electrical and Computer Engineering ETDs

Motion estimation has been dominated by time domain methods such as block matching and optical flow. However, these methods have problems with multiple moving objects in the video scene, moving backgrounds, noise, and fractional pixel/frame motion. This dissertation proposes a frequency domain method (FDM) that solves these problems. The methodology introduced here addresses multiple moving objects, with or without a moving background, 3-D frequency domain decomposition of digital video as the sum of locally translational (or, in the case of background, a globally translational motion), with high noise rejection. Additionally, via a version of the chirp-Z, fractional pixel/frame motion detection …

Scalable Stochastic Reachability: Theory, Computation, And Control, Abraham Puthuvana Vinod

Electrical and Computer Engineering ETDs

Guaranteeing safety and performance are crucial components in any control system, and particularly relevant in light of growing interest in reliable autonomy. In safety-critical applications like biomedical devices, spacecraft applications, and self-driving cars, the cost of failure can be severe. Verification provides these guarantees by characterizing the ``good'' initial states or configurations from which a state can be driven to remain within a collection of pre-specified safe sets, while respecting the system dynamics, bounds on control authority, and additive uncertainties. We also wish to design controllers to achieve this objective. This dissertation proposes novel theory and scalable algorithms for tractable …

Frameworks To Investigate Robustness And Disease Characterization/Prediction Utility Of Time-Varying Functional Connectivity State Profiles Of The Human Brain At Rest, Anees Abrol

Electrical and Computer Engineering ETDs

Neuroimaging technologies aim at delineating the highly complex structural and functional organization of the human brain. In recent years, several unimodal as well as multimodal analyses of structural MRI (sMRI) and functional MRI (fMRI) neuroimaging modalities, leveraging advanced signal processing and machine learning based feature extraction algorithms, have opened new avenues in diagnosis of complex brain syndromes and neurocognitive disorders. Generically regarding these neuroimaging modalities as filtered, complimentary insights of brain’s anatomical and functional organization, multimodal data fusion efforts could enable more comprehensive mapping of brain structure and function.

Large scale functional organization of the brain is often studied by …

Carrier Lifetime Vs. Proton Radiation In Prototype Iii-V And Ii-Vi Space-Based Infrared Detectors, Geoffrey D. Jenkins

Electrical and Computer Engineering ETDs

Researchers have spent over 50 years improving the performance of HgCdTe infrared (IR) detectors and it is currently the dominant technology in the field; however, further improvement may be limited due to devices reaching the intrinsic limits of their constituent materials. To further improve the state-of-the-art in space-based IR detection, alternative material systems are being considered. The focus of this work is testing the space-environment viability of innovative device structures, namely unipolar barriers with Type-II superlattice (T2SL) absorbers, made from the 6.1 Å family of III-V elements which are theoretically superior performers while being less costly.

Sensitive IR photo-detection using …

Cloudsat: Iot Approach To Small Satellite Ground Infrastructure, Brian Zufelt

Electrical and Computer Engineering ETDs

Over the last decade, the cost of space access has dramatically decreased with the creation of the CubeSat standard. The CubeSat standard defines the structural requirements for an on-orbit deployer and satellite to be placed into orbit. The average cost of creating a space mission with the CubeSat standard can range from $200 thousand to over $3 million. This lower cost has allowed many Universities, and small businesses to create their own space programs. However, a significant portion of the investment for any new space asset is the development of the ground system to communicate with the satellite. These costs …

A Novel Indoor Positioning System For Firefighters In Unprepared Scenarios, Vamsi Karthik Vadlamani

Electrical and Computer Engineering ETDs

Situational awareness and indoor positioning of firefighters are types of information of paramount importance to the success of search and rescue operations. GPS units are undependable for use in Indoor Positioning Systems due to their associated mar- gins of error in position and their reliance on satellite communication that can be interrupted inside large structures. There are few other techniques like dead reck- oning, Wifi and bluetooth based triangulation, Structure from Motion (SFM) based scene reconstruction for Indoor positioning system. However due to high temper- atures, the rapidly changing environment of fires, and low parallax in the thermal images, the …

A Narrow-Wall Complementary-Split-Ring Slotted Waveguide Antenna For High-Power-Microwave Applications, Xuyuan Pan

Electrical and Computer Engineering ETDs

A narrow-band, rugged, complementary-split-ring (CSR) slotted waveguide antenna (SWA) with significant size reduction is presented. The antenna is to be vertically front mounted on a land vehicle, with a horizontally polarized fan-beam radiation pattern. The radiation characteristics of a CSR slot in the narrow-wall of a rectangular waveguide are studied for the first time in this work. Both simulation and experimental results show that the complementary-split-ring slot radiates a linearly polarized wave with a total efficiency and gain close to those of conventional longitudinal slots, while the proposed CSR slots have a maximal outer diameter of 0.23λ₀, much …

Oxygen And Silver-Oxygen Defects In Ge2se3 Electrochemical Metallization Bridge Memristors, Jau-Tzuoo Chen

Electrical and Computer Engineering ETDs

We present density functional theory (DFT) calculations of oxygen and silver defects in a crystalline model of amorphous Ge₂Se₃. We studied defects arising from atomic oxygen and dioxygen, as well as interstitial silver and silver displacing germanium, following Campbell's conjecture on the mechanism of dendrite formation. For oxygen defect concentrations below 2%, we show that O₂ dissociates in Ge₂Se₃, oxygen atoms are immobile, and oxygen atoms do not cluster. Within this model, the most preferred oxygen defect in intrinsic Ge₂Se₃ is Ge-O-Ge bridge. We conclude that oxygen defects …

Characterization Of Gallium Nitride Photoconductive Semiconductor Switches In The Nonlinear Regime, Joseph D. Teague

Electrical and Computer Engineering ETDs

The energy demands of an increasingly electrified world have caused a renewed interest in once dormant fields of research. Photoconductive Semiconductor switches (PCSS) are one of these fields. They theoretically offer high voltage, high current switching in sub cm³ packaging, without the shot to shot variation and bulk of current high-power DC switches such as spark gaps. PCSS are capable of power densities of 10⁹-10¹⁰ W/cm³, with electric fields ranging from 10⁵-10⁶ V/cm and current densities from 10⁴-10⁶ A/cm² [1].

Most PCSS make a trade-off between voltage, …

Tunneling In Si Mos Nanostructures, Amir Shirkhorshidian

Electrical and Computer Engineering ETDs

In this dissertation, split-gate tunnel barriers in enhancement-mode silicon metal- oxide-semiconductor (MOS) device structures are characterized electrically at liquid helium temperatures (T = 4.2 K) using transport spectroscopy. Tunnel barriers with different gate geometries and barriers implanted with a small number of antimony donor atoms are characterized. Low disorder MOS tunnel barriers are demonstrated and compared to the implanted cases. The ”clean” MOS tunnel barriers are an important proof of principle that disorder free tunnel barriers can be achieved in MOS. The implanted cases provide an important reference for the effects of donors and shallow traps on a MOS tunnel …

Hand Movement Detection In Collaborative Learning Environment Videos, Callie J. Darsey

Electrical and Computer Engineering ETDs

Human activity detection in digital videos is currently attracting significant research interest. This problem is especially challenging for video datasets that have a lot of human activity, illumination noise, and structural noise. The video dataset associated with the Advancing Out of School Learning in Mathematics and Engineering (AOLME) project has these challenges. ALOME videos have been used in the study of human activities “in the wild”.

This thesis explores detection of hand movement using color and optical flow. Exploratory analysis considered the problem component wise on components created from thresholds applied to motion and color. The proposed approach uses patch …

Capacitive Pcb Security For Active Tamper And Alteration Detection, Casey Petersen

Electrical and Computer Engineering ETDs

The purpose of the research presented is to establish the viability of using capacitive based sensors for the purpose of hardware security at the Printed Circuit Board (PCB) level. Capacitive sensors are traditionally used to sense changes to the areas surrounding the sensing pads in applications such as sensing proximity, position, humidity, fluid levels and much more.

The specific sensor used for this research is an inductor-capacitor (LC) based Capacitance-to-Digital Converter. This configuration is virtually immune to EM noise because it is a tank circuit and therefore filters out the noise which, in the past, caused reliability issues with these …

Pulse Sharpening Circuit For Explosive Emission Cathode Driver, Nicholas D. Kallas

Electrical and Computer Engineering ETDs

Explosive field emission cathodes (EEC), used for the generation of relativistic electron beams, require short rise-time high-voltage pulses in order to minimize the extraction of off-energy electrons. To this end, a rise-time sharpening circuit has been developed at the Los Alamos National Laboratory (LANL). The circuit consists of a 7 nF water-filled peaking capacitor with an integrated self-breakdown switch designed to operate up to -300 kV. This unit is intended to reduce the rise-time of a 4-stage Type-E PFN Marx Generator that will be used to study operational characteristics of velvet cathodes. Simulations of the peaking circuit show a reduction …

Selected Applications Of Silicon Nanopillar Arrays., Behnam Kheyraddini Mousavi

Electrical and Computer Engineering ETDs

Interaction of optical waves with nanostructures made of various material systems has been the subject of intensive research for many years. These researches have been mainly driven by the need to make smaller optical devices and exploiting the functionalities offered by light-matter interaction in nanoscale. Majority of the nanostructures are fabricated using electron beam (e-beam) lithography that is slow and expensive. As such alternative methods have been developed to enable nanoscale fabrication faster and less expensive. Among these interferometric lithography (IL) is a relatively simple method for quick fabrication of nanostructures. As IL method generates periodic patterns, exploring the potential …

Intelligent Computational Transportation, Yuming Zhang

Electrical and Computer Engineering ETDs

Transportation is commonplace around our world. Numerous researchers dedicate great efforts to vast transportation research topics. The purpose of this dissertation is to investigate and address a couple of transportation problems with respect to geographic discretization, pavement surface automatic examination, and traffic ow simulation, using advanced computational technologies. Many applications require a discretized 2D geographic map such that local information can be accessed efficiently. For example, map matching, which aligns a sequence of observed positions to a real-world road network, needs to find all the nearby road segments to the individual positions. To this end, the map is discretized by …

High-Performance Testbed For Vision-Aided Autonomous Navigation For Quadrotor Uavs In Cluttered Environments, Shakeeb Ahmad

Electrical and Computer Engineering ETDs

This thesis presents the development of an aerial robotic testbed based on Robot Operating System (ROS). The purpose of this high-performance testbed is to develop a system capable of performing robust navigation tasks using vision tools such as a stereo camera. While ensuring the computation of robot odometery, the system is also capable of sensing the environment using the same stereo camera. Hence, all the navigation tasks are performed using a stereo camera and an inertial measurement unit (IMU) as the main sensor suite. ROS is used as a framework for software integration due to its capabilities to provide efficient …

Synchronization In An Externally Driven Mechanical Oscillators Experiment, Sumit Chhabria

Electrical and Computer Engineering ETDs

Our experimental system studies the effects of externally controlled oscillation on directly and indirectly driven system of metronomes. This is analogous to many practical systems such as pacemaker effect on heart cells, the external light effect on the suprachiasmatic nucleus in the brain. Here the pacemaker can be compared to an external driving force to the system where the heart cells are our oscillating system. Also, in the suprachiasmatic nucleus cell system, the external input is external light which synchronizes the cell. We explore the synchronization of directly and indirectly driven metronomes due to externally provided forcing.

We designed an …

Multirate Frequency Transformations: Wideband Am-Fm Demodulation With Applications To Signal Processing And Communications, Wenjing Liu

Electrical and Computer Engineering ETDs

The AM-FM (amplitude & frequency modulation) signal model finds numerous applications in image processing, communications, and speech processing. The traditional approaches towards demodulation of signals in this category are the analytic signal approach, frequency tracking, or the energy operator approach. These approaches however, assume that the amplitude and frequency components are slowly time-varying, e.g., narrowband and incur significant demodulation error in the wideband scenarios. In this thesis, we extend a two-stage approach towards wideband AM-FM demodulation that combines multirate frequency transformations (MFT) enacted through a combination of multirate systems with traditional demodulation techniques, e.g., the Teager-Kasiser energy operator demodulation (ESA) …

On Improved Accuracy Chirp Parameter Estimation Using The Dfrft With Application To Sar-Based Vibrometry, Satish Mandal

Electrical and Computer Engineering ETDs

The Discrete Fractional Fourier Transform (DFRFT) has in recent years, become a useful tool for multicomponent chirp signal analysis. Chirp signals are transformed into spectral peaks in the chirp rate versus center frequency representation, whose coordinates are related to the underlying chirp parameters via a computed empirical peak to parameter mapping incorporated into the Santhanam-Peacock algorithm.

In this thesis, we attempt to quantify the accuracy of the DFRFT approach by first studying the discretization error sources that arise from the transitioning of the continuous FRFT to DFRFT. Then, we refine prior work by Ishwor Bhatta to develop analytical expressions for …

Characterization Of Wideband U-Slot Patch Antennas Through Characteristic Modal Analysis And Coupled Mode Theory, Tyler Lapointe

Electrical and Computer Engineering ETDs

Microstrip patch antennas (MPAs) are utilized in many applications as they are easy to produce and are thin, versatile, light weight, cheap, and reliable. One of the drawbacks of MPAs, however, is their narrow bandwidth, typically three to ten percent. Fortunately, a perturbation exists capable of resolving this issue known as the U-slot which can increase the operational bandwidth of a single layer MPA to around 30 percent. Often it is reported that the wideband performance of this structure results from the existence of two resonators, the patch and the U-shaped slot. While this is true, the very nature of …

Optimization Of Supersingular Isogeny Cryptography For Deeply Embedded Systems, Jeffrey Denton Calhoun

Electrical and Computer Engineering ETDs

Public-key cryptography in use today can be broken by a quantum computer with sufficient resources. Microsoft Research has published an open-source library of quantum-secure supersingular isogeny (SI) algorithms including Diffie-Hellman key agreement and key encapsulation in portable C and optimized x86 and x64 implementations. For our research, we modified this library to target a deeply-embedded processor with instruction set extensions and a finite-field coprocessor originally designed to accelerate traditional elliptic curve cryptography (ECC). We observed a 6.3-7.5x improvement over a portable C implementation using instruction set extensions and a further 6.0-6.1x improvement with the addition of the coprocessor. Modification of …

Density And Velocity Measurement Of Ari And Arii Using Laser Induced Fluorescence (Lif) In A Large-Scale Helicon Plasma, Ralph F. Kelly

Electrical and Computer Engineering ETDs

Helicon plasma sources are widely used in basic plasma science, as well as for materials processing. These plasmas typically operate at high gas fill pressure, and therefore have significant densities of neutral particles. However, the role of neutrals in the overall plasma dynamics, such as ion flows, remains poorly understood. There are at least two possible mechanisms for neutrals to influence ion flows. One is an FxB drift, where F is the force exerted on ions by neutrals through collisions. The second is through Pedersen conductivity which is dependent on the ratio of the ion cyclotron frequency, ω …

Split-Ring Resonator Waveguide Structure Characterization By Simulations, Measurements And Linear Time-Invariant Modeling, Mohamed Aziz Hmaidi

Electrical and Computer Engineering ETDs

Interest in Metamaterials has been rising drastically in the recent years as they have been used in several optical and RF applications, from antennas to perfect lenses and pulsed power devices. Nevertheless, the time-behavior of metamaterials remains opaque and poorly understood.

In this research work, characterization of a metamaterial structure in time and frequency-domain was made through simulations and experiments. The structure consists in a series of edge-side coupled Split Ring Resonators (SRRs) in a below cutoff waveguide. A linear time invariant model of distributed elements has been elaborated as well in an attempt to approach the structure’s behavior. The …

Experimental Verification Of A6 Magnetron With Permanent Magnet, Andrew J. Sandoval

Electrical and Computer Engineering ETDs

A compact A6 relativistic magnetron with diffraction output using a transparent cathode, simple mode-converter, and a permanent magnet were simulated and tested at the University of New Mexico (UNM) for the Office of Naval Research. The standard compact MDO with a simple mode converter and transparent cathode radiates a TE11 mode axially through a cylindrical horn antenna. The magnetic field, essential for magnetron operation, is provided by a Neodymium Iron Boron (NeFeB) GradeN40M rare earth magnet. The permanent magnet eliminates the need for a pulsed magnet and accompanying circuit, significantly reducing the size of the system. A permanent magnetic field …

Early Alert Of At-Risk Students: An Ontology-Driven Framework, Elias S. Lopez

Electrical and Computer Engineering ETDs

As higher education continues to adapt to the constantly shifting conditions that society places on institutions, the enigma of student attrition continues to trouble universities. Early alerts for students who are at-risk academically have been introduced as a method for solving student attrition at these institutions. Early alert systems are designed to provide students who are academically at-risk a prompt indication so that they may correct their performance and make progress towards successful semester completion. Many early alert systems have been introduced and implemented at various institutions with varying levels of success. Currently, early alert systems employ different techniques for …

Experimental Testing Of A Metamaterial Slow Wave Structure For High-Power Microwave Generation, Kevin Aaron Shipman

Electrical and Computer Engineering ETDs

Experimental Testing of a Metamaterial Slow Wave Structure for High-Power Microwave Generation

by

Kevin Aaron Shipman

B.S., Exercise Science, University of New Mexico, 2008

A.S., Mathematics, San Juan College, 2014

M.S., Electrical Engineering, University of New Mexico, 2018

Abstract

A high-power L-band microwave source has been developed using a metamaterial (MTM) to produce a biperiodic double negative slow wave structure (SWS) for interaction with an electron beam. The beam is generated by a ~700 kV, ~6 kA short pulse (~ 10 ns) electron beam accelerator. The design of the metamaterial SWS (MSWS) consists of a cylindrical waveguide, loaded with alternating …

Novel Algorithms For Ultra Scale Electromagnetic Problems In The Supercomputing Era, Brian Mackie-Mason

Electrical and Computer Engineering ETDs

The need for increasing fidelity and accuracy in mission-critical electromagnetic applications have pushed the problem sizes toward extreme computational scales. Therefore, there is a large premium placed on the investigation of parallel and scalable integral equation simulators, a particularly useful class of computational electromagnetics, to meet this demand. This dissertation will focus on three interrelated areas: i) quasi-optimal, well-conditioned integral equation based domain decomposition methods, ii) geometry-adaptive, multi-scale discontinuous Galerkin boundary element methods, and iii) high-performance and scalable algorithms to reduce the computational complexity of extreme-scale simulations with the aid of parallel computing architectures. This dissertation will first develop the …

Antennas For Wv Band Applications, Firas Ayoub

Electrical and Computer Engineering ETDs

This dissertation focuses on designing, fabricating and testing antennas that are suitable for operation within the V/W bands. In particular, this work focuses on the design of slotted rectangular waveguide antenna arrays and cross slotted waveguide fed horn antennas. These structures are known for their high efficiency and high circularly polarized gain that can be implemented in satellite and terrestrial communication links. In addition, such designs can be implemented in radar applications that operate infrequency bands around 72 GHz or 84 GHz bands. Such antenna structures are inexpensive to fabricate since they can simply be machined using high precision conventional …